Photoreal Tank in a Crystal Cavern

Ultra-realistic render of a heavy battle tank inside a colossal crystal cavern. The tank is weathered olive-drab with mud on the tracks, visible rivets and wear marks. The cave walls glow with giant quartz crystals, some clear, some opalescent, catching cold blue light. The floor is damp with shallow pools reflecting the tank and crystals. Light beams pierce from ceiling fissures, creating volumetric shafts and soft haze. The camera is at a low angle, slightly off-center, using a 28mm lens, to emphasize scale and depth. The tank's surface has fine scratches, rust patches, and wet reflections. Crystal facets reflect and refract light, producing prismatic glints. The mood is quiet, surreal, and cinematic, with no people present. The overall palette is cool blues, teals, and purples with white highlights.